Wireless repeater system



E. ALSPERRY.

WIRELESS REPEATER SYSTEM. APPLICATION FILED MAR. 12| 1920.

1,428,507, Pafendsept. 5,1922.

3 SHEES-SHEEI I.

I II EIM EL HIS ATTORNE l Patented Sept. 5, 1922.

UNITED STATES PATENT oFFlcE.

ELMER-A. SPERRY, OF BROOKLYN, YORK.

Application led March 12, 1920. Serial No. 365,144.

To all whom t may concern:

le it known that I, ELMER A. SPERRY, a citizen of the United States of America, re-

sidinor at 1505 Albermarle Road, Brooklyn, v

New L )York, in the county of Kings and State of New York, have invented certain new and useful Improvements in Wireless Repeater Systems, of which the following is a specification.

This invention relates to means for automaticallytransmitting the readings of an indicatinfr member by wireless to a distant point. lli/Iy invention is .particularly useful in automatically transmitting by wireless to an aircraft or other distantpoint the readings of a compass, firev control instrument, or other indicator on board a ship, whereby the ships heading or the bearing of a target observed from the ship may be constantly communicated. 4to vsuch distant point.

`. Such a system has especial uses in .the

aerial ordnance control for 'heavy guns where the target is only visible .from air# planes, which signal to the shipor other firing station the bearings of the target. In such a system it is very desirable that the airplane pilot know the bearing of the ship, guns, etc. A

The chief object of. my invention is to provide simple and .eicient means for causing an indicator by meansv of-radiant impulses to` follow automatically the movements of another indicator at a distant point and especially adapted for the use outlined above. Other objects and advantages will become apparentes the description of my invention proceeds.'

A Referring to the drawings wherein'I have shown what I now consider the preferred' forms of my invention: v

Fig. 1 .is a diagrammatic viewvol= one form-'of transmitting apparatus showing the wiring therefor.

Fig. 2 is a Wiring diagram of a receiving apparatus for use in connection with the transmitting apparatus of Fig. 1.'

Fig. 3 is a view of a detail. Fig. 4 is a wiring diagram showing an other form of receiving` apparatus. i, Fig. 5 isa wiring diagram showing still another form of receiving apparatus.

Fig. 6l is a diagrammatic view of one form of' Atransmitting apparatus showing,

' the wiring therefor.

:which are connectedvsparlr plurality of inductances 12, 13, and 14 of -frequencies iof 4 the radiant impulses.

means to bedescribed later only one of said coils or vinductancesat a time 4is laced in `circuit with-thefsource of. E.` M.v

7 is a diagrammatic view of a 'receivlng apparatus' for use with the transmittlnlg' apparatus of Fig. 6.

1g. 8 1s a plan view of an indicating apparatus for use in connection with the receiving apparatus of Fig. 7, the top of the containing 'casing being removed.

. Fig. 9 is a view in elevation of parts of the indicating apparatus of Fig. 8,.the casino' therefor being shown in section. 10,11, and 12 are views of details. In ig. l I have shown at 1 a conventional indicating instrument, which may be a rota- -table compass card or fire control indicator.

Actuated by this indicator in`a manner well known in the art is a transmitter 2 electrically connected with a repeater motor 3. The transmitter 2 and repeater 3 may be of a type well known in the art, such as shown in thepatent to Elmer A. Sperry Serial No. 1,296,440, issued March 4, 1919, for repeater system for gyrO-cOmpaSSeS, or in the a plication for patent by Elemer Meitner, Sleirial No. 227,680, filed April 10,1918, for self-setting transmission system. The repeater motor may be of the six pole type having three sets of coils 4, 5, and 6, and

,an armature '7.v

For communicating to a distant point th indications or steps of the armature of repeater motor 3, I" have provided means whereby, as the respective sets of coils of repeater 3 are energized, radiant impulses..`

of different frequencies are sent, each -of which frequencies corresponds to one set of coils of a repeater motor 8 at said distant station. Various means may be provided for transmittingwireless impulses of, 'different frequencies inaccordance with the particular coils of repeater" 3 which are ener ized. One form of such means is shown 1n. 1g. 1

and may be constructed substantially as fol` lows: l v

The wirelesssending apparatus may be of lany conventional type. For instance, it may comprise a source 9 of E. M. F., connected to an induction coil 10, to the secondary of gap lland a,

different? values [corresponding to difer-)Iit y Each lso

.coil may cooperate withan open oscillatory circuit consisting of an antenna 12 and earthed coils 16, 17,y and 18 cooperatingl with coils 12, 13, and 14, respectively.

The means for placing coils 12, 13, and 14 successively in circuit With generator 9 may take various forms, one of which. is shown in Fig. 1, and, more in detail, in Figs. 10, 11, and 12.` SaidA coils are shown each connected at one end with a wire 19 leading to one terminal of the induction coil and at their other ends with brushes 28 engaging members 20, 21, and 22, respectively. The -latter n'iembers are shown in Figs. 1() and 12 mounted. on conductingf'sleeve 24 on shaft 23, which sleeve is connected by wire 25 with the induction coil. bers conu'irises a double contact portion 26 and insulation portions 27 as shown in Fig. l). 'lhe contact portions of members 20, 21, and 22 are in engagement with sleeve 24 a d may be so arranged .that when a Contact portion of one member passes out from under its cooperating brush, a contact portion of the next contact will come under its corresponding brush, and so on. Sleeve 24 is shown separated by insulation 29 from shaft 23. F rom the construction above described it will now be evident that, if shaft 23 he rotated to follow the movements of repeater 3, and the contact portions of members 20, 21, and 22 be suitably arranged with respectto 'said shaft, one of coils l2, 13,' and 14 corresponding with the particular setv 4, 5, or 6 of the coils of r`epeater 3 which is energized, will be connected in the sending circuit. Shaft 23 might be connected directly with the armature of repeater motor 3, but owing to the possibility o1 the motor falling out of step it overloaded,`1 prefer to employ in connection therewith a followsupsystem.

As shown in Fig. 1, the aforesaid fol-low'- up system may comprise a trolley 30 rotatable with the armature of repeater motor 3 and connected by a conductor 31 with one terminal of a battery 32 or other source of EfM, F., the other terminal of which source ofln. M.F. may he connected with one terminal of a motor." 33. The other terminal of the motor may be connected as shown with oppositely wound field coils 34 and 35., which coils are connected at their other ends with contact portions 36 and 37 respectively of a drum 38 fixed to shaft 2.3. The latter shaft is drivenby the motor 33. \Vhen armature 7 is at rest, trolley 3() rests on a strip of insulation between contact portions 36 and 37. When, however, said armature moves in one direction or the other", it will be evident that current will flow through motor 33 and one or the other of field coils 34, 35 thereby causing motor 33 to turn in suchdirection as t0 brin the aforesaid strip ofinsulation again un ery trolley 30. Shaft 23 and the Each of' said mem- `contact members mounted thereon are thus turned to follow-up the movements of re- 1 shown, Asix contact segments 39 are provided and are suitably connected to conducting hub 40. The latter is engaged by a brush 42 connected by conductor 43 to a relay magnet coil,44, which coil is connected as shown to one terminal of battery 32. rl`he other terminal of said battery is shown connected with 'a brush 45 in engagement with the periphery of member The armature 46 of'relay coil 44 is shown adapted to` close a circuit through generator 9 and induction coil 10 when said armature is attracted by said coil. Normally the armature is held by a spring 47 in a position in which the aforesaidcircuit is open. f

The operation of the above described apparatus will now be readily understood. As indicator 1 turns', transmitter 2 is actuated and armature 7 and trolley 30 are caused to more step-by-step. As armature 7 commences to turn through a. step, motor 33 is energized to turn shaft 23 through the same step or angle as armature 7turns. lre'ferably, contact segments 39 of member 38-v are so arranged that the circuit through coil 44 is closed at some point during the turning 'of shaft 23 through said step or angle and opened again by the time the turning through said step has been completed, since if said circuit is closed at the exact time that turning through said step is completed, impulses will be sent continuously until the shaft 23 again commences to turn. At the time the circuit through coil 44 is closed,- the contact portion of the proper one of members 20, 2l, and 22 has been brought under its cooperatlng brush so that that one ofcoils 12, 13, and 14 which correspomls with the yenergized set of repeater coils is connected in the wireless sending ci rcuit. (lonsequently an impulse of a frequency corresponding to the aforesaid set of repeater coils will have been sent by the time shaft 23 resl'ionding to that through which armature 7 has turned. [n other words` l'or each `step of said armature` an impulse corresponding in 'frequency with the set of repeater coils energized is sent. -l. have shown sixcontactl segments on member 38, whereby the circuit of the wireless transmission system will be closed six times during one revolution of the repeater. It is evident, however, that, where has been turned through an angle colthe repeater has -twelve steps per revolution, as is the casein the patent to Sperry aforementioned, twelve contacts might be .arranged on member 38, whereby twelve w1reless impulses per revolution of the repeater' shaft 23 can be driven directly by indicator v1 in the same manner as transmitter 2, and

that transmitter 2, repeater 3, and the follow-up motor may be omitted from the connection between' said indicator and said shaft.

In Fig. 2 I have shown one form of wireless receiving means adaptedto cause the energization of the lproper set of coils of a repeater motor 8 according to the frequency of theimpulses received. Each set 48,59, and50 ofthe repeater coils is shown connected at one end to a common con- "ductorl leading to one terminal of a source l engaged by the relay armatures 56, 57, and

58. Said armatures are shown connected with the other terminal of source 52 of E. M.- F. Repeater motor 8 may be geared or otherwise connected, as is well known in the art, with a repeating lindicator 8.

A conventional open oscillatory circuit is shown at 59, coupled with` which are a plurality'of closed oscillatory circuits including 'coils 6L), 61, and 62. In circuit with said coils are suitable detectors of electrical oscillations, such .detectors being indicated at 63, 64, and-65. Coils 60, 61, and 62 cooperate with earthed 'coils 66, 67, and 68 of the aforesaid' open oscillatory circuit and are eachresponsive to a different one of the frequencies sent by. the transmitter `magnet. Coils 69, 70, and 7 1 are.interposed in the closed oscillatory'circuitsas shown 'and are adapted to attract armatures 56, 57, and 58, respectively,fto close circuits through the 'y sets of coils of the4 repeater motor 8.

Inasmuoh as the armatures of the conventional repeater motors of the type shown are not polarized, it follows that the repeater may easily fall out of step with the transmitter if none of the coils of the reexternal forces. Accordingly I have provided the polarized relays shown so lthat. when one of said relays is energized 1t will close a circuit through `the corresponding set of repeater coils and maintain such circuit closed until another set of coils'is energized. The armatures 56, 57, and 58 may be polarized in any suitable andconventional manner. In y series with coil -69 are coils A72 and 73 adapted, when energized, to withdraw armatures 57 and 58 from engagement with their respective contacts. Likewise, in series with coil 70 are coils 74 and adapted to withdraw armatures 56 and 58, while in series with coil 71 are coils 76 and 77 adapted to withdraw armature-s 56 and 57.

The operation of the above described receiving apparatus will nowbecome evident. Assuming that an impulse is sent of a frequency corresponding to repeater coils 4 and to which coil 60 and detector 63 are responsive, coils 69, 72, and 73 are energized. Armature 56 is thus attracted to cause energizationof set 48 of the repeater coils and simultaneously armatures 57 and 58 are kept out of en gement with their respective contacts. V-hile the impulse may be of only brief duration, armature 56, being polarized, will remain in engagement with contact 53 and keep set 48 of the repeater coils energized. Saidset of coils will remain energized until an impulse of a different frequency is sent. Thus, if an impulse of a frequency to which coil 61 is responsive is sent, such frequency corresponding with repeater coils 5, armature 56 will be withdrawn from engagement with contact 53 and simultaneously coil 'ZQ will be energized to attract armature 57 and cause energization of set 49 ofthe repeater coils. If, on the other hand, an impulse of a frequency to which coil 62 is responsive and corresponding with repeater coils 6 were sent, armature 56 would be withdrawn from en- 110 gagemet with contact 53 and simultaneously coil ,71 would be energized to'attract -armature 58 tocause energization of set 50 of the repeater coils. In this manner the armature of repeater motor 8 lwill be main- 11.5 tained in synchronis'm with motor 3 and indicator 1. Y. p In Fig. 4 I have shown, an alternative arrangement' whereby 4'twelve steps per" repeater rotation may be obtained at the receiving station. .In this case,'two six pole repeater motors 78 and 78 may be so connectedwith thev shaft 80, which actuates a suitable indicator, that the coils of one are displaced thirty degrees with respect to the corresponding coils of the other. Thus, if l the sets of coils of one motor are energiz`ed in between the energizations ofV the sets of coilsof the other motor, the shaft 80 will be moved through steps of thiity de-v grecs cach. For causing the-coils of the aforesaid motors to be energized in the proper' sequence I have shown connections similar to those shown in Figx, except that six closed oscillatory circuits, including coilsI 81 to 80, responsive to different frequencies, are provided. In this case it is obviousthat twelve impulses per revolution of the repeater 3 should be sent, as by providing twelve contact segments on member 88. Also, it will be evident, that six dierent frequencies should be provided in the trans- Init-tinge apparatus in place of the three shown, the frequencies corresponding to successivc steps of the repeater through 180". Inasmuch as -it will be obvious to those skilled in the art, after inspection of Fig. 1, howv six different inductan'ces in place of three maybe connected iny the transmission circuit to obtain the desired results,lfurther illustration is thought unnecessary.

The sets of coils of repeater 78 I have designated as 87, 88, and 89, while those of re.- peater 78 are designated as 87', 88', and 89. As shown, sets 87, 88, and 89 are connected at one end to vone terminal of battery 79 and the other ends of said sets of coils are connected with contacts 91,93, and 95. Sets of coils 87', 88',' and 89 are likewise connected at one end with the aforesaid terminal of battery 79 and the other ends of said coils are connected with contacts 92, 94., and 90. Contactsv 90 to. 95, inclusive. are adapted to be engaged by armaturesI of pol arized relays of the type shown in Fig. 2, said ,armatures bcingcon'nected with the other terminal of battery 79.

The operation of the construction shown in Fig. 4 will now be readilyapparent. As-y suming that coils t'of motor 3 are energized vand that an impulse'of a frequency vcorresponding thereto`is sent, to which frequency coil 82 is responsive, the armature which cooperates wi th contact`91 will be attracted to close a circuit through coils 87 of therepeater 78. If now, coils 5 of repeater motor 3 are energized while coils 4 remain energized the armature of 'said motor will n1ove through thirty degrees and an impulse of afrcquency to which coil 83 is responsive will be sent. A circuit through coils 87 of motor 7 8 will thereupon be closed and simultaneously therewith the circuit through coils 87 of motor 7 8 will be broken. If, on the other hand, while coils 4t remain energized, coils 3 had heen energized, an impulse to which coil 8l is responsive would have been sent, which would have Vresulted in the simultaneous closing` of a circuit through coils 89' of repeater motor 7 8' and breaking of the circuit through coils 87 of repeater motor 78. The indicator actuated by motors 78 and78'V may thus be moved step-by-step in either direction an kept in synchronism with indicatori. y

tures, 99, 99', and 99", respectively, which armatures are adapted to be attracted to engage contacts connected with the other terminal of battery 98. The armatures may be normally biased by springs, as shown, to

a position in which the respective circuits through the repeater coils are open. When, however, one of relay coils 100, 100', and 100 is energized, the corresponding armature will be attracted to close a circuit through the corresponding repeater coils, and said armature ewill remain in its 4attracted position as long as current (lows through the rel'ay coil. Coils 100, 100', and 100" may be comiected in closed oscillatory circuits including inductances 101, 101', and 101",and coherers 102, 102', and 102", the aforesaid inductances being` responsive to different frequencies and the aforesaid oscillatory circuits cooperating` with open oscillatory circuits comprising antenna 103, as shown. Adjacent the coherers are decoherers. Each decoherer is arranged to be actuated to render its corresponding cohcrer non-conducting when either of the circuits control-led by the other coherers and their corresponding relays'is closed. While the decohcrers may assume various forms I have herein shown them as respectively comprising tappers 105, 105', and 105", which are adapted to he attracted to tap the respective coherers. Magnet coils 106, 106', are shown cool'ierating with tapper 105, the former coil being in circuit with repeater coils, 9G' and the latter with` repeater coils 96". Similarly associated with tapper 105 are coil 107 in circuit withlrepcater coils 9G and coil 107' in circuit with repeater coils 96", while associated with tapper 105" are coil 108 in circuit with repeater coils 96 and coil 108' in circuit with coils 96'. Assuming that coils 4l of repeater 3 are energized and that an impulse ofv a frequency to which coil 101 is responsive is sent, it will be seen that armature 99v willbe attracted toclose a circuit through repeater coils 96 and that simultaneously tapperslO and 105" will be attracted to render coherers103 and 102" non-conducting.. Armature will now re main attracted until coherer 21,02 is tapped toy ow through relay coil 100, and armature 99 will be retracted by its spring to break the 'circuit through repeater coils96. If, on the otherl hand, coils 6 of repeaterl 3 had been energized, armature ,99 i would have been attracted to close a circuit through coils 96 and tappers 105 and 105 would have been attracted, with the result that armature 99 would have been retracted to break the circuit through repeater coils-96. Thus, when a set of the coils of repeater 97 is energized, said set remains energized until the next set is energized whereupon the rst set is simultaneously deenergized. It is thus evident that, when synchronism between repeaters 3 and 97 is once established Vit will be automatically maintained.

In Figs. 6-9, inclusive, I have illustrated another form of my invention wherein impulses of only two different frequencies need be utilized to reproduce at a distant point the movements of an indicator. In Fig. 6, the parts corresponding with similar parts in Fig. 1 are designated by the same numerals with a prime added. As has been heretofore indicated, it is immaterial what particular form of Wireless transmitting and receiving apparatus is employed and it is evident that various types of apparatus may be utilized. In the "form shown diagrammatically in Fig. 6, different frequencies may be obtained by throwing more or less of tuninglcoil 109 into circuit by actuating contact arm 110 to engage one or the other of contact points 111, 112. For actuating arm 110 to 'cause an im-A pulse of the proper frequency to be sent at the correct time I may employ apparatus constructed and arranged substantially as follows: l'

Cooperating with arm 110, as shown, are

. solenoids or magnets 113, 114 which may be connected at one end with one terminal of battery 32'and at their other ends with armatures 115, 116, respectively, which armatures are adapted to engage contacts 117, 118. The latter contacts may be connected as shown with brushes 119, 120, respectively, which brushes engage the conducting hub portion 40 of a mem er 38f mounted on and insulated from shaft 23'. Member 38. is similar to member 38 of Fig.. 3 and is pro vided with conductin segments 39' electrically connected with ub 40 and insulated from each other. I prefer to provide twelve segments 39' corresponding with twelve steps per revolution of the repeater 3', but, of' course, thenumber of such se ents-may be varied as desired. Adapte to cooperate with thev aforesaid contact segments successively is a brush member 124 which may be connected in an suitable wa with the battery 32. It ollows' from tfe structure above described that, ifbrush 124 be engaged with a segment 39' and if one or the other of armatures 115, 116 be attracted to engage its corresponding contact, a circuit will be closed throughfthe corresponding one of solenoids 113,114, whereupon an impulse of correspondin frequency will be sent. For attractin die above mentioned armatures, I have s ownl magnet coilsl 125, 126, which may be in circuit with ield coils `35', 36', respectively. Thus, when motor 33 turns in one'direction, impulses of one frequency may be sent,` and, when sald motor turns in the other direction, impulses of another frequencymay be sent.

From the above describedconstruction it will beapparent that, as long as the re- 'peater motor 3' moves in one direction, curas vdesired in order that impulses of the desired duration may be sent.l

One form of indicating means Iat thereceiving station, for use in connection with a transmittin system of the type just described, is s own in Fi s. 8 and 9 and may be constructed substantially as follows:

An indicator shaft 127,'whichmay carry an indicator 1281nay be mounted in bearings 129, 130 in a caslng 131. Indicator 128 may cooperate with a. suitable scale 132. Of course shaft 127 may actuate a repeating indicator through 4reduction .gearing or otherwise, as is well known in the art.- Mounted ixedlyl on shaft 127 are ratchet wheels 133,134, having oppositely, directed ios teeth. Eachratchetwheel is, inthe example shown, provided with` twelve teeth corresponding with twelve steps. of repeater motor 3. For actuating said ratchetwheels I have shown pawls 135, 136, pivoted to the ends of members 137, 148, respectively,

which members are inturn suitablypivoted f at their other ends to brackets 139, 140 in casing 131. Springs 141,114.2, interposed be-l tween members 137, 138, and casingfll, serve to retract pawls 135, 136 .from engagement with the correspondingfratchets. v. Said pawls are preferablyrbiased byl 144 towards engagement with t e teeth of the corresponding wheels,l auth-.when retracted,

Springs 1.435.

solenoids 147, 148 is energized, one or the y13| other ol' pawls 135. 136 will he pushed into engagement with the corresponding,r ratchet wheel to turn shaft 127 through one step in vthe desi red/'direetion. vWhen current ceases to low through said solenoid, the pawl will he retraeti-d by the eorresimnding one of springs lLl-l` H2 into a position out ot the path oil its ratchet. wheel. lt will now be seen that il solenoids lll-7, lflS are so connected in Vthe. wireless receix-'ingr circuit that, when .impulses olI one 'frequency are sent, one solenoid is energized, and when impulses oli' another frequency are sent, the other solenoid is energized, indicator 128 will 'follow the movements ot repeater motor 3. (lne ot the various 'forms which said circuit connectiiinsmay assnn'ie is shown in Fig'. 7.

ln Fig. 7, 160 is an antenna and 161 a suitable tuning device.. ,ll deiiotes a snitable detector which is influenced by impulses transmitted when, lor example, contact arm l l() is in engagement with contact point cill. and 152 isla deter-.tor which is influenced when .contact arm ll() is in engagement. with contact point i12.` ln circuit with said detectors are shown a. battery 1525 and relay magnets 154, 15,5. Controlled through relay armature 15G, are solenoids 147, 148 said solcnoids being shown in circuit with a. loattei'y 157, and relay contacts 158, 15S), respectively. 0

'lhe operation ot the form ot my invention shown in lligs. (l, 7, 8,'andv9 will now clear. For each step ot' repeater motor 3 in one direction, one of solenoids 147, 1.18 will beA energized, and indicator 128 moved throi'igh one step each time that said solenoid is energized. Likewise, When repeater motor 5l moves in the reverse direction, the other of solenoids 147, 't4-S is energized and deener- 'f gized during each step ot the repeater motor, and indicator '128 is thereby moved in the reverse direction. lt will thus be apparent that indicator 12S will he maintained in step with repeater motor l/Vhile a suitable .brake olany desired type may be provided inv .connection with sha l't 127 to prevent accidental movement ol said shaft when no impulses are ,being sent, I have not illustrated such brake since it is evident that the same result may be obtained by Y nroviding sufficient 'triction between the shatt and its bearings.

While I have chosen for purposes of illustration to show shaft 127 as actuating an indicator it will be evident to those skilled inthe art that said shaft may carry transmitter contacts or otherwise actuate a transmitter,

which transmitter may be electrically `conquencies may easily be provided, as, for

example, in the manner above disclosed, tor

the operation of the repeater system.

In accordance with the provisions ot the patent statutes, I have herein described the principle oit operation of my invent-ion, together with the amiaratus, which I now censider to represent the best embodiment thereol" but l desire to have it uinflerstoml lthat the apparatus shown is only7 illustrative and that the in vcntion can be carried ontby oihcl' means. Also` while it is designed to use the various icatnres and elements in the combination and relations described, some.- ot these may be altered and others omitted without interfering;` with the more general resi dts out lined, and the invention extends to such use.

fllavinzc` described my invention, what I claim and desire to secure. by Letters latent is: i

1. In combination, ai pair ot step-ly-step re} eater motors, and wireless means lor causing.,r one. ot' said motors lo lollow the movements ot' the other of said motors in either ot opposite directions.

2. In'combinatioman indicator, means responsive to radiant impulses ot a lgiven `treqnency lor moving,r said indicator stepbystep in one. direction, and means responsive to radiant impulses otanother frequency for moving said indicator ste] )-by-ste p in another direction. y

3. A repeater system toraerial ordnance control comprising the combination with a ships bearing imlieato'r oli a 'wireless sending instrument controlled thereby, a' repeating-indicator adapted to be mountedv on an aircrat,a repeater motor for actuating the same, and a Wireless receiving device adapted to control the energization of said motor.

4. A repeater system for aerial ordnance contr-ol comprising the combination with a ships bearing indicator,l of Wireless transmission means controlled thereby, means for automatically -varying the frequency of the wirelesstimpulses in accordance with the direction of movement of said indicator, a rcpeating indicator adapted to be mounted on an aircraft, and means responsive to said impulses for actuating said repeating indicator in accordance with the movement of said ships bearing,T indicator.

5. A repeater system for aerial ordnance control comprising the combination With a ships bearing indicator of 'a step-by-step repeater motor controlled thereby, Wireless transmission means, follow-up means interposed between said motor and said means for effecting the control of said means by said motor, a repeating indicator adapted to be mounted on an aircraft, and means responsive to Wireless impulses for controlling said repeating indicator.

6. Airepeater system for aerial ordnance control comprising the combination with a ships bearing `indicator of Wireless transmission means controlled thereby, a repeate ing indicator adapted to be mounted on shipfao board, and means -responsive. to wireless impulses for causing' movement of said indi.

cator. v

7, In combination with an indicator, a repeater motor controlled thereby, a fol1ow-`up motor controlled by said repeater motor, and lWireless, transmission means controlled by said follow-up motor.v

8. In combination with a repeater motor, a follow-up motor controlled thereby, means controlled by said follow-up motor for transmitting Wireless impulses, and means controlled by said follow-up motor for varying the frequency of said impulses. 9. A repeater system for aerial ordnance control comprising the combination with -a ships bearing indicator of means controlled thereby for sendingn Wireless impulses, means controlled by said indicator for automati-v cally varying the frequency of said impulses,v a repeating indicator adapted to be mounted on an aircraft, and means responsiveLto said iimpulses for actuating said repeating indicator. fs y I- f l p 10. The combination with a ships gyro,` scopic` compass having a transmitter, of a wireless sending instrument adapted to be actuated therefrom, comprising a repeater motor connected to said transmittergreversing contacts actuated thereby, a reversible motor also connectedthereto and in circuit therewith and radio-impulse transmission means actuated by said reversible motor.. f

.11. The combination withl a ships gyoscopic compass having a transmitter, of a Wireless sending instrument adapted to `lbe actuated therefrom, and a wireless receiving instrument. adapted to be located on anair craft and actuated from said sending instru# ment including an indicator showing the `heading of the ship on which said compass is mounted v v I 12. The combination with a ships. -gyroe scopic compass having a transmitter, ofa

wireless sending instrumenty adaptedto lbe y' actuated therefrom, comprising a repeater motor connected to said transmitter, contacts actuated thereby, a Second motor also conncted thereto and in circuit therewith and radio-impulse transmission means actuated by said second motor.

In testimony whereof I yhave aiiixedmy Y signature.

ELMER A.v s PERRY.' 

